1. Summary of the Invention
The present invention relates to a new orthopaedic implant system of the type formed of a supporting structure fitted with at least one orifice to let through a fastening screw associated with a nut.
2. Description of the Related Art
Generally speaking, orthopaedic implants, in particular osteosynthesis implants, include a supporting structure in the form of a plate, a shell or other, fitted with one or of several orifices intended to let through fastening screw able of being anchored in the receiving bone material.
The general shape and the dimensions of this supporting structure are adapted to the implantation constraints.
There exist a very large number of types of implants which differ in particular by the presence or not of an interconnection between the screw head and the supporting structure, to optimise retention of the screw over a long period of time, and/or the presence of means conferring to the fastening screw a possibility of angular orientation relative to the axis of its reception orifice, to enable the practician position at best said screw relative to the site of implantation and to the corresponding spatial constraints.
Good holding quality of the implant is obtained when the supporting structure is sandwiched between the screw head and a nut, as known from the document WO-A-99/09903. But in such a case, the particular interconnection of the nut with the supporting structure requires accurate introduction of the fastening screw so as not to damage the thread of the nut during the screwing operation; and the practician has no possibility of orienting the screws spatially.